What is URL Encoding?
URL encoding, also known as percent-encoding, is a mechanism for encoding special characters in a URL so they can be safely transmitted over the internet. URLs can only contain a limited set of characters from the ASCII character set. When a URL contains characters outside this set — like spaces, accented letters, or special symbols — they must be encoded into a format that is safe for transmission.
In URL encoding, each unsafe character is replaced by a percent sign (%) followed by two hexadecimal digits representing the ASCII code of the character. For example, a space becomes %20, the ampersand (&) becomes %26, and the equals sign (=) becomes %3D.
Common URL Encoded Characters
- Space → %20 (or + in some contexts)
- & (ampersand) → %26
- = (equals) → %3D
- ? (question mark) → %3F
- # (hash) → %23
- / (forward slash) → %2F
- : (colon) → %3A
- @ (at sign) → %40
- + (plus) → %2B
- % (percent) → %25
When Do You Need URL Encoding?
- Query string parameters: When passing user input in URLs like search queries or form data
- API requests: When making REST API calls with parameters containing special characters
- Email links (mailto: links): Subject lines and body text with special characters must be encoded
- Redirects: When building redirect URLs that contain other URLs as parameters
- Data in URLs: JSON, base64, or any structured data passed via URL parameters
Frequently Asked Questions
What is the difference between encodeURI and encodeURIComponent?+
encodeURI encodes a complete URL, preserving characters like /, :, ?, and # that have special meaning in URLs. encodeURIComponent encodes a URL component (like a query parameter value) and encodes ALL special characters including /, :, ?, and #. Our tool uses encodeURIComponent, which is appropriate for encoding individual values that will be passed as URL parameters.
Why does a space become %20 in some places and + in others?+
Both represent spaces, but in different contexts. %20 is the standard percent-encoding for a space and works everywhere. The + sign represents a space specifically in the query string of form-encoded data (application/x-www-form-urlencoded format). In modern web development, %20 is generally preferred for clarity.
Is URL encoding the same as URL escaping?+
Yes, URL encoding and URL escaping are different names for the same process — replacing special characters with their percent-encoded equivalents. The terms are used interchangeably in web development contexts.
Can I decode a URL that someone sent me?+
Yes. Paste the percent-encoded URL into the Decode section of our tool and click Decode URL. The tool will convert all %XX sequences back to their original characters, making the URL human-readable. This is useful for understanding complex URLs with many parameters.
Does URL encoding affect SEO?+
Yes, indirectly. URLs with special characters should be properly encoded to ensure search engines can crawl and index them correctly. Non-encoded special characters in URLs can cause crawling errors. Additionally, clean, readable URLs (with hyphens instead of encoded spaces) are generally better for both SEO and user experience.